Diastereochemical differentiation of [beta]-amino acids using host-guest complexes studied by fourier transform ion cyclotron resonance mass spectrometry

• Published in: Journal of the American Society for Mass Spectrometry 2007-06, Vol.18 (6), p.1038
• Main Authors: Hyyryläinen, Anna R, M, Pakarinen, Jaana M, H, Vainiotalo, Pirjo, Stájer, Géza, Fülöp, Ferenc
• Format: Article
• Language: English
• Subjects: Amino acids; Chemical bonds; Cyclotron resonance; Fourier transforms; Hydrogen bonding; Ionization; Ions; Mass spectrometry; Mathematical analysis; Scientific imaging; Selectivity; Spectroscopy; Stereoselectivity; Supramolecular compounds
• ISSN: 1044-0305; 1879-1123
• DOI: 10.1016/j.jasms.2007.03.002

Host-guest complexes where tetraethyl resorcarene was the host molecule were used to study the stereoselectivity of diasteromeric pairs of di-endo- and di-exo-2,3-disubstituted norbornane and norbornene amino acids by ion-molecule reactions and collision-induced dissociation with electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI FT-ICR MS). Both methods showed stereoselectivity for the diastereomeric pairs. Particularly high selectivity was achieved for di-endo- and di-exo-2,3-disubstituted norbornane amino acids with ion-molecule reactions. Also, ab initio and hybrid density functional theory calculations were performed to study the different structures of the host-guest complexes. Hydrogen bonding was crucial for the calculated lowest energy structures, and sterical considerations satisfactorily explained the ion-molecule reaction results.